Blackberry plant named ‘Driscoll Eureka’

ABSTRACT

The present invention relates to a new and distinct cultivar of blackberry plant named Driscoll Eureka. The new cultivar is distinguished from other blackberry cultivars by its early season, low chill requirement and improved quality and shipping characteristics. The new cultivar is distinguished from its seed parent by being early and having better flavored fruit, it is distinguished from its pollen parent by its better flavor.

Latin name of the genus and species of the plant claimed: The variety isbotanically identified as Rubus L. subgenus Rubus.

BACKGROUND OF THE INVENTION

This invention relates to a new cultivar of blackberry called ‘DriscollEureka’ . The new cultivar was developed from hybridization of thefemale cultivar ‘Zorro’ (U.S. patent application Ser. No. 09/772,327)with the unpatented male selection BY45.1. The parents were crossed in1996 where after fruit and seed were collected to produce seedlings forfield planting in Watsonville, Calif. in 1997. The new cultivar wasselected in 1998 for its good flavor and fruit firmness. The cultivarhas been asexually propagated in Watsonville, Calif. and reproduced trueto type plants by in vitro shoot tip culture.

SUMMARY OF THE INVENTION

The present invention provides a new and distinct blackberry cultivarnamed ‘Driscoll Eureka’. The variety is botanically identified as RubusL. subgenus Rubus. The variety is a complex Rubus hybrid, which can becharacterized as an erect tetraploid with considerable R. allegheniensisbackground with other species such as R. trivialis, R. argutus, R.procerus, and R. ulmifolious also appearing in its background. The newcultivar produces a floricane crop which begins in May and continuesuntil late July. The new blackberry variety is distinguished from othervarieties by a number of characteristics as set forth in Table 1. Inparticular, the new cultivar is distinguished by its early season, itslow chill requirement, and its improved quality and shippingcharacteristics.

COMPARISON TO SIMILAR VARIETIES

The variety that we believe to be similar to ‘Driscoll Eureka’ fromthose known to us is ‘Olallie’, an unpatented variety. ‘Driscoll Eureka’is particularly different from ‘Olallie’ by being slightly earlierripening, having less postharvest color reversion, having less acidicflavor, and having better fruit firmness. Further detailed comparison of‘Driscoll Eureka’ to ‘Olallie’ and ‘Chester’ is presented in Table 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying photographs show typical specimens of the fruit, leavesand shoot of the new cultivar, in color as nearly true as reasonablypossible in color illustrations of this type.

FIG. 1. is a photograph of a ‘Driscoll Eureka’ fruiting lateral withfruit in various stages of development.

FIG. 2. is a photograph showing a close-up view of a primocane shoot,mature leaf and stem of ‘Driscoll Eureka’.

DESCRIPTION OF THE NEW VARIETY

The following detailed description of the new blackberry cultivar,‘Driscoll Eureka’, is based upon recorded observations of 2 to 5 yearold plants and fruit grown between 2000 and 2002 in Watsonville, Calif.and is believed to apply to plants of the ‘Driscoll Eureka’ cultivargrown in similar conditions of soil and climate elsewhere. Plants wereplanted in soil previously pre-plant fumigated and regularly fertilizedand irrigated with drip irrigation. This description is in accordancewith terminology used by the International Union for the Protection ofNew Varieties of Plants (UPOV). Throughout this specification, colornames beginning with a small letter signify that the name of the color,as used in common speech, is aptly descriptive. Color data with acapital letter and an alphanumeric code indicate the most similar colordesignations as provided by The Royal Horticultural Society (R.H.S.)Colour Chart published by The Royal Horticultural Society of London,England. Color designations, color descriptions, and other phenotypicaldescriptions may deviate from the stated values and descriptionsdepending upon variation in environmental, seasonal, climatic andcultural conditions.

CHARACTERISTICS OF THE NEW VARIETY

Table 1 provides information on the plant and fruit characteristics ofthe new blackberry cultivar ‘Driscoll Eureka’ compared withcharacteristics of the unpatented blackberry cultivars ‘Olallie’ and‘Chester’. Both ‘Olallie’ and ‘Chester’ are currently importantcultivars for fresh market shipping, and thus are comparable to theproposed use of the new invention, ‘Driscoll Eureka’. Observations of‘Driscoll Eureka’ ‘Olallie’ and ‘Chester’ were taken in side-by-sidecomparison in 2001 and in 2002.

Fruit of the new cultivar is particularly characterized anddistinguished from other cultivars by its improved flavor and shippingcharacteristics. Drupelets of ‘Driscoll Eureka’ fruit show lesspostharvest color reversion compared to ‘Olallie’, the most comparablecultivar fruiting at the same time of the season.

‘Driscoll Eureka’ is moderately productive and produces most of its cropin the early part of the harvest season. Canes of ‘Driscoll Eureka’ arevigorous, thorny and have buds with a low chill requirement. The averageplant height is about 279 cm and the average plant spread is about 169cm.

The style pigmentation color is 143B, the average number of styles perflower is about 112, the anther pigmentation color is 155A, and theaverage number of anthers per flower is about 121. The number of petalsper flower is five. The color of the sepal pigmentation is 144A. Thecolor of the seeds of ‘Driscoll Eureka’ is 152C and the average seedweight is 2.9 mg.

‘Driscoll Eureka’ is distinguished from its pollen parent, BY45.1, byhaving better flavor.

‘Driscoll Eureka’ is distinguished from its seed parent, ‘Zorro’, bybeing earlier and having better flavored fruit.

TABLE 1 PLANT CHARACTERISTICS OF ‘DRISCOLL EUREKA’ Driscoll EurekaChester Olallie GENERAL Vigor moderate- high moderate- high high Growthhabit semi-erect semi-erect spreading Productivity moderate high highSelf-fruitfulness self- self- self- fruitful fruitful fruitful Time ofbud burst early late early CANES Primocanes Young shoot pigmentationweak medium weak glucosity (waxy bloom) absent or medium weak weak canecross section angular to angular to rounded to (from mid cane of groovedgrooved angular primocane) dormant cane color brown to purple brownbrown to purple purple brown Spines present absent present pigmentationpurple — purple color 184A — 187A density on young shoots medium —medium attitude of tip downward — downward to horizontal size medium —medium size: Length (base to tip)(mm) 3.4 — 3.0 texture smooth — heavypresence and distribution on present — present petioles irregularlyirregularly distributed distributed Pubescence on canes present presentpresent LEAVES Relief between veins medium weak medium Number ofleaflets usually 5 usually 5 sometimes 3 sometimes 5 Glossiness mediummedium medium Leaf cross section concave concave concave to flatTerminal leaflet length (cm) 8.6 10.7 9.1 width (cm) 7.2 8.3 7.9 shapeovate ovate ovate tip acuminate acuminate acuminate base cordate cordatecordate margin doubly doubly doubly serrate serrate serrate Lateralleaflet length (cm) 7.9 9.2 8.4 width (cm) 5.5 6.4 6.3 shape ovate ovateovate tip acuminate acuminate acuminate base rounded to rounded roundedcordate margin doubly doubly doubly serrated serrated serrated rachislength (between 3.0 3.0 2.5 terminal leaflet and adjacent lateralleaflets) (cm) overlapping of lateral overlapping overlappingoverlapping leaflets Petiole length (cm) 6.2 5.9 3.9 pigmentation ofupper surface red red green to purple/ purple/ slightly maroon maroonpink 183A pigmentation of underside yellow green yellow green yellowgreen 146A Stipule orientation clasping erect clasping to erect Colorface 147A 146A 146A underside 147B 146A 146A FLOWERS Flowering period(time of very early very late early beginning of flowering) Flower sizemedium medium medium Flower diameter (cm) 4.8 4.3 4.3 Flower number (at3^(rd) 5.0 9.5 4.2 node from tip of lateral mean and range) Petal length(cm) 2.3 2.0 2.0 width (cm) 1.7 1.4 1.3 Pedicel coloration absent weakvery weak length (cm) 2.4 1.8 — FRUIT Fruit harvest season early lateearly Color black black black immature 187A 187A 187B maturing 202A 202A202A mature fruit 202A 202A 202A Glossiness strong medium medium Shapeovate round to narrow ovate ovate Dimensions fruit size medium smallmedium large length (cm) 2.3 2.1 2.9 width (cm) 2.0 2.0 1.7 Weight(g/fruit) 4.2 3.9 5.3 Soluble solids (%) 11.9 9.6 10.4 Titratableacidity (% as 1.34 1.84 2.06 citric acid) (ml. of added .1 N NaOH to pH8.1) Number of druplets per fruit 61 46 86 Firmness firm firm soft

NUCLEIC ACID FINGERPRINTING

Distinctive patterns of polymorphism can be detected using a variety ofnucleic acid analysis methods. In one non-limiting example, moleculargenetic maps can be produced using random amplified polymorphic DNA(RAPD) (Williams et al., 1990, “DNA polymorphisms amplified by arbitraryprimers are useful as genetic markers”, Nucleic Acids Res.18(22):6531-5). Using a variety of oligonucleotide primers, alone or incombination, RAPD analysis of Driscoll Eureka, Chester, and Olallieyielded DNA fragment patterns that uniquely distinguish each of thesegenetically distinct genotypes.

We claim:
 1. A new and distinctive cultivar of blackberry plant,substantially as shown and described.